1. Field of the Invention
The present invention relates to a method and apparatus for turning over pages of a book-original, i.e., a bound book to be used as an original for copy or facsimile transmission applied to a copying machine or a facsimile apparatus.
2. Description of the Related Art
As an original reading device for a copying machine or a facsimile apparatus, there has been known an automatic document feeder (ADF) which automatically feeds a sheet of original to a scanning position of the device where the original is read and automatically discharges the original from the scanning position after the original is read.
As mentioned above, if the original is composed of sheets of paper, it is possible to automatically read information from the original by using the ADF. However, if the original is composed of a bound book, the pages of the original book has to be turned over by hand since there has been no practical automatic page turning over device realized until now.
With respect to such a book-original, various kinds of methods and apparatuses have been proposed to automate the reading and turning over operation of the book-original which is very troublesome and time consuming.
However, the proposed techniques are merely ideas of desire and far from the level of practical use.
The techniques in relation to the method and apparatus for automatic book-original reading and turning over pages are proposed in, for example, Japanese Patent Applications Laying Open (KOKAIs) No.54-21836 titled "READING DEVICE 0F COPYING APPARATUS", No.61-28449 titled "AUTOMATIC PAGE TURNING OVER DEVICE FOR BOOK TYPE ORIGINAL", No.56-60294 titled "PAGE TURNING OVER DEVICE FOR BOOK", No.60-122932 titled "IMAGE FORMING DEVICE", No.63-47197 titled "AUTOMATIC PAGE TURNING OVER DEVICE", No.63-47198 titled "AUTOMATIC PAGE TURNING OVER DEVICE", No.63-49743 titled "ORIGINAL TREATMENT DEVICE", No.63-49744 titled "ORIGINAL TREATMENT DEVICE", No.63-49745 titled "ORIGINAL TREATMENT DEVICE", No.63-49746 titled "ORIGINAL TREATMENT DEVICE", No.63-49747 titled "ORIGINAL TREATMENT DEVICE", No.63-49748 titled "ORIGINAL TREATMENT DEVICE", No.63-49749 titled "ORIGINAL TREATMENT DEVICE", No.63-50825 titled "ORIGINAL TREATMENT DEVICE", No.63-50826 titled "ORIGINAL TREATMENT DEVICE", No.63-50827 titled "ORIGINAL TREATMENT DEVICE", No.63-50828 titled "ORIGINAL TREATMENT DEVICE", No.63-51192 titled "ORIGINAL TREATMENT DEVICE", No.63-41192 titled "PAGE TURNING OVER DEVICE", No.63-42895 titled "AUTOMATIC PAGE TURNING OVER DEVICE", Japanese Utility Model Application Laying Open (KOKAI) No.63-43141 titled "ORIGINAL TURNING OVER DEVICE", Japanese Patent Applications Laying Open (KOKAIs) No.63-67191 titled "PAGE TURNING OVER DEVICE", No.63-67192 titled "PAGE TURNING OVER DEVICE", Japanese Utility Model Application Laying Open (KOKAI) No.63-41588 titled "DEVICE FOR TURNING OVER PAGES OF BOOK", Japanese Patent Applications Laying Open (KOKAIs) No.62-267196 titled "SAFETY DEVICE FOR PAGE TURNING OVER DEVICE", No.62 -267197 titled "SAFETY DEVICE FOR PAGE TURNING OVER DEVICE", No.62-234462 titled "IMAGE SCANNER", No.63-33738 titled "COPYING MACHINE", No.62-273892 titled "PAGE TURNING OVER DEVICE" and No.63-64797 titled "PAGE TURNING OVER DEVICE".
Of all the almost unpractical proposed techniques, there are some useful ideas which have possibility of realization for practical use such as the technique described in the patent documents 61-284492 and 62-35891. The technique adopts a method for turning over pages of a book-original wherein the pages are turned over in such a way that the book is opened at a page to be read and placed with the page being downward on a scanning plate and that the book is shifted while the page is being sucked so that the page is separated and turned over.
However, in accordance with the above mentioned proposed technique, since the book is placed and moved on the scanning plate with the page to be read being downward, the page surface rubs the plate surface with being pressed by the weight of the book, which adversely acts on the function of turning over the page, thus decreasing the reliability of the device.
Also, the structure of the device of the related art page turning over technique is bulky and complicated.
It is to be noted that there is proposed another technique of the related art wherein the original turning over arrangement is made in such a way that the book is opened and placed with the page to be read being upward and that the page is turned over by mechanical means such as a roller or an arm or vacuum means. However, such an arrangement makes the whole structure of the copying apparatus bulky since the large space is necessitated for the page turning over device to move above the book-original.
Also, in accordance with the page turning over device of the related art, the page is not reliably turned over.
Referring now to another point of the related art, when a book-original is to be read or scanned for copy, for instance, the ranges spanning several pages in the middle of the book are usually to be read which ranges are not continuous each other.
It is desirable that the pages in the ranges be automatically read and turned over to raise the functionability of the book-original turning over and reading device for the sake of easy manipulation of the device.
However, the page turning over device of the related art does not comprise means for automatically turning over the pages in a specified range of the book-original.
Therefore, in accordance with the page turning over device of the related art, the operator has to open the book and set the desired page in the range, which takes much time to scan the pages of the range and makes the device inconvenience to manipulate.
On the other hand, from the another point of view, each paper of almost all of the book-originals (more than 90 percents) has information printed to be read or scanned on both sides thereof.
Therefore, the first page to be read can be either the left side page or the right side page of the book opened and placed on the scanning plate.
Accordingly, if the first page to be scanned is not indicated, the unnecessary page may be read, instead, which wastes a copy and time for reading the necessary pages and impairs the convenience of the device.
Also, in accordance with the page turning over device of the related art, the pages of the book-original are turned over by moving the device with respect to the book placed on the scanning plate.
Therefore, if the device is moved back without the page being securely held, the motion of the device may be disturbed so that a stable motion of the device is not realized.
Referring still another aspect of the page turning over device of the related art, in accordance with the device wherein the book-original is placed being opened with the spread pages to be scanned being upward, the original page surface becomes curved instead of flat due to the spine of the book.
Accordingly, if the scanning device is constructed so that the spread pages are scanned by a scanning optical system which is moved along the original in a state of being in contact with the original surface, unless the book-original is pressed against the plate to be flattened or the optical system is moved along the curve of the original page, the original can not correctly be imaged and read since focal point of the optical system becomes dislocated due to the curve of the original surface.
Especially, if the optical system is constructed from an equimultiple optical system, the dislocation of the focal point of the optical system becomes large since the allowable focal range of the system is small.
Also, if the optical system is constructed so that it scans the original with being in contact with the page surface, the optical system rubs the page surface and the functional reliability of turning over the pages is reduced, which then impairs the scanning reliability of the system.
Also, in the above mentioned device of the related art, the book-original is read and pages are turned over by moving an original reader unit having a page turning over means with respect to the book-original placed on the scanning plate.
It is desirable that such a related art device comprise a pressing means for holding the book-original down against the scanning plate at the time of reading operation. However, from the point of mechanical structure, it is difficult to combine such a pressing means and the scanning system. Therefore, the related art device does not comprise a pressing means for pressing the spread pages of the book-original against the plate to flatten the pages to be scanned, which degrades the reliability of scanning the original and turning over the pages of the book.
Especially, if the device is so constructed that the scanning system or the page turning over means moves on and along the original with being in contact with the spread pages of the original book, it becomes further difficult to realize the stable function of scanning the original and turning over the pages, since the original page surface is easily moved and dislocated.